Hello Paul,
why do you say that they are not right? It is relatively easy to set, however, either by ear with a piece of hose or with an air flow gauge.
The basic procedure is to disconnect the link between the two carburettors then adjust the idle so that both are equal in air flow, keeping to the idle speed you want, then reconnect the throttle.
If you then blip the throttles you should see the pistons rise more or less at the same rate. This is not a procedure that should need doing very often, indeed there is little requirement to adjust these once set up. They do not go out of tune, just keep the dashpots topped up and occasionally clean inside the dashpots and pistons with a solvent cleaner.
Alec